To assess prognostic/predictive value of carcinoembryonic antigen (CEA), transthyretin (TRT), αenolase (NNE), β2-microglobulin (β2-micro), B-cell activating factor (BAFF) and circulating tumor cells (CTCs) in metastatic colorectal cancer (mCRC) patients treated with chemotherapy with or without bevacizumab.